Fire-bridge for boiler or the like furnaces.



G. H. BUTTERWORTH & R. CANLIN. FIRE BRmGE FOR BOILER on THE L'IKE FuRNAcEs.

APPLICATION FILED MAY 4, 1912. l

Patented Apr. 27, 1915.

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G. H. BUTTERWORTH R. CANLIN.

FIRE'BRIDGE FOR BOILER OR THE LIKE FURNACES.

APPLICATION FILED MAY 4, 1912.

Patented Apr. 27,1915.

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ETMIEE FAIEE'VI FFIEE.

GEORGE HERBERT BUTTERWORTI-I AND ROWLANI) CANLIN, 0F GREAT CROSBY, NEAR LIVERPCQL, ENGLAND.

FIRE-BRIDGE EOR BOILER 0R THE LIKE FUBNACES.

Specification of Letters Patent.

Patented Apr. 27, i915.

Application led May 4, 1912. Serial No.`695,7258.

To all whom it may concern i Be it known that we, GEORGE HERBERT BUTTERWORTH and RowLAND CANLIN, subjects of the King of Great Britain, and residing at Great Crosby, near Liverpool, in the county of Lancaster, England, have invented certain new and useful Improvements in F ire-Bridges for Boiler or the like Furnaces, of which the following is a specification.

This invention has reference to ire bridges of the hollow type adapted to admit air from the ash-pit into the space above or beyond the lire bars, the object being to simplify and cheapen the construction and to so arrange the component parts that cleaning and renewals may be effected expeditiously and cheaply.

According to our present invention the perforated part of the bridge is carried by a rectangular Vbase plate, and is built up of a number of sectional arch pieces carried on a slide or bed attached to the base plate. The arch-pieces are identical in shape and are of such conguration that when as sembled, they form with two end plates, a complete hollow perforated arch, the perforations being formed between the successive arch pieces. Each arch piece may form a complete section of the arch, or there may be two arch pieces, one at the back and one at thel front to form the complete section, in which case there are overlapping parts of half thickness. Each arch piece has a dove-tail extension which fits in a dove-tail groove in the slide or bed, the arrangement being such that the dove-tail extensions serve to hold the arch pieces in position on the bed.

One important feature of the present in- Y vention is, that if the arched part of the sectional arch pieces burns away there is no increase in the available air passages, these remaining constant as the arch-pieces are burnt away.

It will be seen that a bridge built up of arch pieces which are identical in shape offers great advantages in respect to renewal, since there is practically but the one kind of spare part to be stocked, and that this part can be used to renew any section of the bridge arch; and as the perforations are formed by coinciding recesses in the sectional arch pieces all the perforations may be divided laterally for cleaning, by a slight lateral separation of the arch pieces. The invention, as applied to the furnace, of say, a marine boiler, is illustrated in the accompanying drawings, in which,

Figure l is a longitudinal view showing the bridge in position in the furnace, Fig. 2 being a corresponding transverse section on the line II, II, of Fig. l. Fig. 3 is a plan of the bridge, to a larger scale, the sectional arch-pieces being omitted from the right hand side, and some of the front halves of these being omitted from the left hand side; Fig. 4f is a corresponding elevation, the ri` ht hand half being in section on the line IV, IV, of Fig. 3, and showing the right hand end section in position. Fig. 5 is an end elevation and Fig. 6 a corresponding end elevation in section on the line VI, VI, of Fig. 3. Figs. 7 and 8 are fragmentary sections on the lines VII, VII, and VIII, VIII, of Fig. 4. Figs. 9 and 10, and 9A and 10A are respectively elevations and plans of front and back sectional arch pieces shown apart, Fig. 10B being a side view of Fig. 10. Figs. 11 and 12 are an elevation, anda plan of these two pieces assembled together, and Fig. 13 is an elevation similar to Fig. 11, but to a larger scale of two of the sectional arch pieces assembled together, Figs. 14: and 15 being corresponding sections on the lines XIV, XIV, and XV, XV, of Fig. 13. Fig. 15A shows a modification.

The base-plate A is in the form of an open rectangular frame which is fitted transversely across the furnace, being xed in position by the lugs al; the base-plate has a ledge a2 to take the ends of the lire-bars B, and it is usually fitted with a depending plate C provided with door c1 to permit ashes being raked out from behind the bridge. To the base-plate is fixed a slide or bed D, which in the example illustrated is made in the form of two side rails secured to the base plate by the lugs d1 each side rail being made in two lengths joined at the lugs cl2. Each rail is framed to form a series of openings cl3, and the inner bar d* of each rail forms, with the corresponding bar of the other rail, a dove-tail slot d5 the beveled edges of the rails forming the dovetaildbeing cut away at each end as shown at 6.

sloping lower edges of the pieces resting onV the sloping parts of the rail d4. The pieces are inserted in the dove-tail slot at' the cut away `ends where the latter Widen out and thenlslid lalong Still' the dove-tail en-A gages I `ig. 8 shows, in section, the arch piece Vbeing inserted, and Fig. 7 shows it in position in the dove-tail.

The central: overlapping parts et of the sectionalarchpieces are half the thickness of the unperforated parts so that when the kpieces are assembled 'air can pass as shown "by the arrow-heads in Figs. 6 and 13: Two end plates Fare fitted which are vhollowed on the: outside face so asto facilitate shaping to fit the interior contour of the furnace. It will'v be Vseen that'if the'sectional arch pieces Aburn away, even down to the line P, Q, Fig.Y 13 there will be no material increase in the cross sectional area of the air pasy vrsages'thr:ough'the bridge since the remaining central p artsc* maintain thisarea practically constant. The arrangement 'v illustrated is as stated one designed for' furnaces in: boilers of the marinetype, butthe details of the invention can be modified within the limits of the inventioiiv' to suit particular requirements.

Y Forfinstance, while it is found most convenient to make the section arch pieces in halves with" overlapping central portions of half fthi'cliness,th`e two halves mayl obviously be made 1integral a's `shown in the right hand archf'p'viece of Fig". liand in Fig. 15A which is-'a view analogous to Fig. 15; the shape ofthe sectional arch pieces may also be modifiedvto give a different section of hollow bridge, the distance pieces being? arrangedto vsuit 'the perforations required for vsuchsection; and the slide or bed may be madej'integral with the base platejand it and the corresponding part" of the sectional vvvarg'zh-pieces Vbe modified in'shape'to give anyvsuitable mode of connection of the sectional arch pieces to the base plate.

Having now fully described our inven- V 'tilon, we declare that what we claim, and de- 555 sire'to secu're'by Letters Patentis;-

1; In a fire bridge, in combination, a pair of railsextending acrossthe furnace, supportingA means therefor, an arch formed'of aseriesof arch pieces each consisting of' two sections,` each of said arch pieces comprismg a web,y which in transverse elevation 1s co-e'xtensiveiwith the arch piece as a whole,

and aseries ofdistance facings on each side off the web adapted, when the archpieces are assembled to Yform the arch, to abutf and form air-ways between the webs, substantially as described.

2. In a fire bridge, in combination, a pair of rails extending across the furnace, supporting means therefor, an arch formed of a series of arch pieces each consisting of two sections, each of the said arch pieces comprisinga web, which in transverse elevation is coextensive with the arch piece as a whole and which-is provided with a depending extension adapted to engage with the rails, and a series of distancefacings on each side of the web adapted, when the arch pieces are assembled to form the arch, to abut and form air-ways between the webs, substantially as described.

3. In a'fire bridge, in combination, ay pair of rails extending across the' furnace, supporting means'therefor, an archl formed of a series ofl arch pieces each' consisting of two sections, each of said arch pieces comprising a web, which in transverse elevation is co-extensive with theA arch piece as a whole, and a series of distance facings on each side ofthe web located so as to leave a margin of web outside the facings, said distancefacingstbeing adapted, when the arch pieces are assembled to form the arch, to abut and form air-ways between the webs, substantially as described.

4. In a iireb'ridfge, in combination, a pair of rails extending across the furnace, supporting meanstherefor, an arch formed of a series of pairs of AOverlappingsections each of which extendsV across and is carried by perforated =extensions on the rails, each pair 0fI overlapping sections forming arr arch piece comprising a web extending'from the periphery of thel arch to the extensions, and aser'ies ofithin'distancepieces on each side' of the web, the distance pieces of adjacent arch pieces being 'in contact and leaving parallel'r air-waysA between the arch pieces, substantiallyv as described.

y5'. In afire bridge, in combination, a pair ofirails' extending' across th'efurnace, supporting 'means therefor, an arch formed of a series ofpairs of overlapping sections each of`which extends across and is carried by perforated extensions on the rails, the edges of said' extensions forming a dove-tail re- ,cess and the said overlapping parts being on the webs so as to leave a margin of web outside the distance pieces, substantially as described.

7. In a fire bridge, in combination, a pair of rails extending across the furnace, supporting means therefor, an arch formed of a series of pairs of overlapping sections each of which extends across and is carried by perforated extensions on the rails, each section having a central part of triangular configuration and of reduced thickness, said parts of opposite sections of a pair being adapted to overlap and form the center of the web of an arch piece, substantially as described.

8. In a fire bridge, in combination, a pair of rails extending across the furnace, supporting means therefor, an arch formed of a series of pairs of overlapping sections each of which extends across and is carried by perforated extensions on the rails, each section having a central part of triangular configuration and of reduced thickness provided with a dove-tail attachment extension, said parts of opposite sections of a pair being adapted to overlap and form the center of the web of an arch piece, substantially as described.

9. In a fire bridge, in combination, a pair perforated extensions on the rails, the rear side of the arch being formed of sections separate from but identical in shape with and interchangeable with those forming the front side, substantially as described.

10. In a fire bridge, in combination, a pair of rails'extending across the furnace, supporting means therefor, a series of arch pieces provided with centrally located dovetail depending lugs, said rails having internally projecting extensions provided with passage-ways and adapted to form a bed for the sectional arch pieces and to engage said depending lugs, the said extensions being out away at the ends of the rails, substantially as described.

1l. In a lire bridge, in combination; the sectional arch pieces; the transverse rails having internal perforated extensions, and supporting means for the rails, said perforated extensions forming a bed with reversely sloped sides, said sectional arch pieces having correspondingly sloped webs with dovetailed extensions resting on and fitting said reversely sloped sides of the bed, substantially as described.

In testimony whereof we affix our signatures in presence of two witnesses.

GEORGE HERBERT BUTTERWORTH. ROWLAND ANLIN. Witnesses:

J. S. LLOYD BARNES, JOSEPH E. I-IIRsT.

Gopies of this patent may be obtained for ive cents each, by addressing the Commissioner of Patents. Washington, D. C. 

